Asagi Koi
Asagi is koi's ancestral aristocrat - the closest living variety to the original ornamental carp, wearing a blue-grey net of perfectly aligned scales over its back with fire-red flaring along the belly, cheeks and fins.
🗓️ Last reviewed: July 2026
Overview
Asagi is koi's ancestral aristocrat - the closest living variety to the original ornamental carp, wearing a blue-grey net of perfectly aligned scales over its back with fire-red flaring along the belly, cheeks and fins. Understated beside modern brights, it rewards the eye that values order: every scale in its row, every row in its place.
Natural History
One of the oldest varieties (200+ years), ancestral to many others; its blue reticulated scale pattern traces straight back to the first colour mutations of Niigata food carp.
Appearance
Indigo-to-sky-blue reticulated (net-pattern) back, red (hi) rising from belly and pectorals, ideally a clear light head; to 60-90 cm.
Tank Size & Setup
Koi-standard pond; Asagi's subtle beauty reads best in clear, light-bottomed water with overhead viewing.
Water Parameters
Standard koi range; clarity is the variety's stage.
Diet
Seasonal koi feeding; moderate colour-enhancement (heavy carotenoids can blush the blue).
Health & Lifespan
Average lifespan is 25-40 years. Koi-standard hardiness and decades; hi (red) may creep upward with age - part of the fish's story.
Pros & Cons
Pros
- Living koi history
- Exquisite scale-net precision
- Calm, classic pondscape presence
- Pairs beautifully with bright varieties
Cons
- Subtle - not a beginner's wow
- Head clarity often imperfect
- Red creep can unbalance with age
- Show-grade netting is rare
Asagi Koi - frequently asked questions
What should I look for in an Asagi?
Even, unbroken scale reticulation over the whole back, clean blue tone, a clear head and balanced belly-red - order is the entire aesthetic.
Is Asagi related to Shusui?
Directly - Shusui is Asagi's scaleless (doitsu) twin, keeping the blue back and red flanks with only a dorsal scale row. Same palette, different texture.
Why does my Asagi get redder each year?
Hi tends to advance with age in the variety - charming to some, unbalancing to judges. It's the fish writing its autobiography.
🧠 Test yourself: guess the fish
Three clues from our quiz bank, each about another of our fish. Can you name them?
Clue 1.Diamond-shaped with long flowing dorsal and anal fins, this popular tank fish needs a tall aquarium to accommodate its towering body.
It's the Angelfish - read the full profile →
Clue 2.This vast family of often colorful, territorial fish includes the angelfish, oscar, and the discus, plus the species swarming Africa's Rift lakes.
It's the Cichlid (Overview) - read the full profile →
Clue 3.Unlike most aquarium fish, this beginner-friendly group gives birth to free-swimming young instead of laying eggs.
It's the Molly / Platy / Swordtail (Livebearers) - read the full profile →